Heat exchanger

ABSTRACT

The invention relates to a heat exchanger ( 10 ) for heating flowable media, in particular highly viscous materials, coating materials, or the like, comprising a profile body ( 11, 12 ) having at least one flow channel segment ( 13, 14, 15, 16 ) of a flow channel of the heat exchanger, and a heating unit disposed in the profile body, wherein the heating unit comprises at least two electric heating elements ( 22, 24 ). A first heating element ( 22 ) is disposed in a heating element receptacle ( 23 ) formed in the profile body, and a second heating element ( 24 ) is disposed in a sleeve element ( 17 ) of the heating unit, wherein the sleeve element is disposed in the flow channel segment formed in the profile body, such that the heating elements are sealed against the flow channel.

The invention relates to a heat exchanger for heating flowable media, inparticular high-viscosity materials, coating materials, or the like,comprising a profile body having at least one flow channel section of aflow channel of the heat exchanger and a heating device, which isarranged in the profile body, the heating device having at least twoelectrical heating elements.

Heat exchangers of this type are sufficiently known and are regularlyused as a continuous flow heater for heating coating materials in thefield of spraying technology. The coating material is conveyed by meansof a pump through the flow channel of the heat exchanger, heating of thecoating material being performed through the contact thereof with heatexchanger surfaces inside the flow channel. Electrical heating elementsare typically used for generating the heat energy, which are arranged ina body of the heat exchanger that forms at least a section of the flowchannel. The heating element or elements must be arranged in the body insuch a manner that uniform heating of the flow channel occurs. It isdisadvantageous here in particular that the heat transfer from theheating elements to the coating material only occurs indirectly and thebody, which is formed from metal, must first be heated.

Furthermore, embodiments of heat exchangers are known in which a heatingelement is arranged directly in the flow channel. Rapid and effectiveheating of the coating material is possible here, however, in the caseof the comparatively small heat exchanger surface of the heatingelement, the danger exists of overheating of the coating material. Thecoating material can also easily bake or accumulate on a heating elementsurface, which can in turn result in clogging of the flow channel. Incontrast, a comparatively smaller temperature gradient between a flowchannel inner surface and the coating material is achievable with thearrangement of the heating elements in the body, but in this case acomparatively long flow channel must be implemented to implement arequired larger heat exchanger surface. A more complicated channel guideor a more complex structure of the body results therefrom in adisadvantageous way, in particular since the heat exchanger isfrequently used in combination with a mobile spraying device and musttherefore be relatively compact in its dimensions.

Cleaning of the flow channel is also frequently necessary, for example,in the event of a change of the coating materials, in the event ofclogging, or after ending a coating procedure, the heat exchanger and inparticular the flow channel typically being cumbersome to disassemble ordifficult to clean. This is predominantly the case in the heatexchangers known from the prior art, since the flow channel forms bendsor curves in the body, which can only be reached using a cleaning toolwith difficulty or which require time-consuming disassembly of the heatexchanger.

The present invention is therefore based on the object of proposing aheat exchanger which has a simple and compact, easy-to-clean structureand nonetheless allows improved heat transfer.

This object is achieved by a heat exchanger having the features of claim1.

The heat exchanger according to the invention for heating flowablemedia, in particular high-viscosity materials, coating materials, or thelike, comprises a profile body having at least one flow channel sectionof a flow channel of the heat exchanger and a heating device arranged inthe profile body, the heating device having at least two electricalheating elements, a first heating element being arranged in a heatingelement receptacle implemented in the profile body, and a second heatingelement being arranged in a sleeve element of the heating device, thesleeve element being arranged in the flow channel section implemented inthe profile body in such a manner that the heating elements are sealedin relation to the flow channel.

In particular the heating of the profile body using a heating elementand the use of the sleeve element, which is also heated, in the flowchannel section allow particularly effective heat transfer to theflowable medium, since the effectively heated heat exchanger surfacesare relatively large. The flowable medium thus comes into contact with aflow channel inner surface and a sleeve element surface, which areheated by the first or the second heating element, respectively. It isadvantageous that the flow channel section is implemented by a profilebody, which is geometrically uniform and therefore easy to clean. Aprofile body does not have bends or openings, in which possibleaccumulations could only be removed with difficulty, and is additionallysimple to produce and available in arbitrary lengths. Because of theeffective heating, the flow channel of the heat exchanger can bedimensioned as relatively short, without a heating element coming intodirect contact with the medium. Local overheating of the medium also canhardly occur in the flow channel section because of the uniform heatdistribution via the heat exchanger surfaces implemented in this manner.The negative effects connected thereto are thus avoided in particularbecause the heating elements cannot come into contact with the medium.

The heat exchanger can advantageously comprise a plurality of profilebodies arranged in parallel. A flow rate can thus be increased oralternatively a flow channel section can be lengthened. The heatexchanger can in particular be implemented so that a modular structureof the heat exchanger having a number of profile bodies suitable for therespective application is possible. Adaptation of the heat exchanger tospecial customer wishes or requirements is therefore easily possiblewithout greater production expenditure.

The heat exchanger can also comprise a cover element and a base element,which are each arranged on profile ends of the profile body. Forexample, a plurality of profile bodies can be mounted between the coverelement and the base element by means of the cover element and the baseelement. The cover element and the base element can also be sealed inrelation to the profile ends so that the flowable medium cannot exitfrom the heat exchanger in an undesired manner.

Attachment channels of the flow channel can also be implemented in thecover element and/or in the base element. The attachment channels thendo not have to be arranged in one or more profile bodies, but rather cansimply be arranged on the above-mentioned elements, depending on the userequirement of the heat exchanger. A plurality of connection channelscan also be provided on different sides of the cover element and/or thebase element for optional use. The unused attachment channels can thenbe closed using a screw connection, for example.

It is particularly advantageous if at least one connection channel forconnecting flow channel sections is implemented in the cover elementand/or in the base element. Multiple flow channel sections can thus beconnected one behind another in series. The number of connectionchannels can vary depending on the number of profile bodies used.Therefore, it is merely necessary to replace cover element and/or baseelement having the corresponding number of identical profile bodies toimplement heat exchangers having different heating powers.

An advantageous mounting of the sleeve element is possible if the sleeveelement is fixedly connected to the cover element. To clean the flowchannel, the cover element must then merely be disassembled from theprofile body, the cover element then being removed together with thesleeve element from the profile body or from the flow channel section.The sleeve element surface and also the flow channel inner surface arethus easily accessible for cleaning. The first heating element, which isarranged in the heating element receptacle of the profile body, canpreferably also be connected to the cover element in a suitable manner.

The heat exchanger can be produced particularly simply if the flowchannel section and the heating element receptacle are implemented aspassage boreholes in the profile element in the longitudinal directionof the profile element.

In order to implement a heat exchanger surface which is greatly enlargedin relation to a conventional heating element, the sleeve element canimplement a polygonal cross-section.

If the sleeve element has a plurality of longitudinal groovesdistributed around the periphery on its peripheral surface, in such amanner that the sleeve element forms a star-shaped cross section, a heatexchanger surface or sleeve element surface can be enlarged stillfurther.

Particularly large heat exchanger surfaces are possible if an externaldiameter of the sleeve element essentially corresponds to an internaldiameter of the flow channel section. A flow channel cross-section isthen solely implemented by the intermediate space, which is annular incross-section, between flow channel inner surface and sleeve elementsurface.

A plurality of partial channels of the flow channel section can thusalso be implemented between the sleeve element and the profile body. Ifthe sleeve element surface at least sectionally comes into contact withthe flow channel inner surface, a particularly good seat of the sleeveelement in the flow channel section is additionally ensured.

In an advantageous embodiment, the heat exchanger can have heatingelements in a ratio of two second heating elements to one first heatingelement.

A simple, joint attachment of all heating elements to a power supply orsubdistributor is made possible if the heat exchanger has an attachmentdevice for attaching the heating elements on the cover element. Theattachment device can comprise a housing, which is sealed in relation tothe surroundings, having devices for the subdistribution for theelectrical heating elements and control or regulating devices.

At least one temperature sensor can be arranged in the flow channel toimplement a temperature regulation. Multiple temperature sensors canoptionally be provided to ascertain a temperature differential along theflow channel. A temperature regulation can preferably be performed basedon measured values of the temperature sensor using a programmable logiccontroller (PLC).

The flow channel itself can be implemented as meandering, for example,by flow channel sections arranged in series one after another, which areconnected via connection channels. A compact embodiment of the heatexchanger can thus be implemented particularly simply.

The heat exchanger can advantageously have an insulation device, whichminimizes possible heat losses to an environment. Furthermore, theinsulation device can protect operating personnel from possible burns.

The invention is explained in greater detail hereafter with reference tothe appended drawings.

In the figures:

FIG. 1 shows a first perspective view of a heat exchanger;

FIG. 2 shows a second perspective view of the heat exchanger;

FIG. 3 shows a cross-sectional view of the heat exchanger in aperspective view;

FIG. 4 shows a longitudinal sectional view of the heat exchanger in aperspective view;

FIG. 5 shows a longitudinal sectional view of the heat exchanger in aperspective view;

FIG. 6 shows a partial longitudinal sectional view of the heat exchangerin a perspective view.

A consideration of FIGS. 1 to 6 together shows a heat exchanger 10 invarious perspective views and sections. The heat exchanger comprises twoprofile bodies 11 and 12, which implement flow channel sections 13 and14 or 15 and 16 like a passage borehole. Furthermore, sleeve elements 17are arranged in each of the flow channel sections, which have astar-shaped profile cross-section 18, so that a plurality of partialchannels 21 is implemented between a flow channel inner surface 19 and asleeve element surface 20. Furthermore, the heat exchanger 10 comprisesfirst heating elements 22, which are arranged in a heating elementreceptacle 23, which is implemented in the profile body 11 or 12 and isimplemented like a passage borehole. Second heating elements 24 arearranged in the sleeve elements 17 in sleeve element receptacles 25,which are also implemented as a passage borehole. The first heatingelements 22 and second heating elements 24 are each arranged in theheating element receptacles 23 or 25, respectively, so that a touchcontact exists for particularly good heat transfer between the firstheating elements 22 and the profile bodies 11 or 12 and between thesecond heating elements 24 and the sleeve elements 17. In order toprevent penetration of a flowable medium (not shown here) into theheating element receptacle 25, a sealing screw 27 is screwed into thesleeve element 17 at a lower end 26 of the sleeve element 17 in eachcase.

Furthermore, the heat exchanger 10 comprises a cover element 28 and abase element 29, which are arranged on profile ends 30 to 33 of theprofile bodies 11 or 12 and are fixedly screwed thereon by means ofscrews 34. Furthermore, two connection channels 35 and 36 areimplemented like a transverse borehole in the base element 29 and areeach closed using a screw 37. The connection channel 35 connects theflow channel sections 13 and 15 and the connection channel 36 connectsthe flow channel sections 14 and 16, respectively. A connection channel38 having a screw 37, which connects the flow channel sections 13 and14, is also provided in the cover element 28. Furthermore, attachmentchannels 39 and 40 are implemented like a borehole in the cover element28, which are connected to the flow channel sections 15 or 16.Attachment screw connections 41 for attaching the heat exchanger 10 to asupply line or drain line (not shown here) of a spraying device arescrewed into the attachment channels 39 and 40. Overall, through therelative arrangement of the flow channel sections 13 to 16 and theconnection channels 35, 36, and 38, a meandering implementation of aflow channel 42 results.

Seals 43 are arranged on the profile ends 30 to 33 to seal the coverelement 28 and the base element 29 with the profile bodies 11 and 12.Furthermore, the sleeve elements 17 are provided on their upper ends 44with a peripheral groove 45 and a thread 46. The sleeve elements 17 arethus fixedly screwed into the cover element 28 by means of the thread46. The peripheral groove 45 is essentially used for improveddistribution of the medium to be heated.

Furthermore, an attachment device 47 having an attachment housing 48 andan attachment terminal 49 is arranged on the cover element 28. Theattachment terminal 49 is essentially used for the electrical connectionof the first heating elements 22 and second heating elements 24 to acentral power supply. The attachment housing 48 is formed from a housingring 50 having a housing cover 51, which are connected to the coverelement 28 so that a sealed attachment chamber 52 is formed.

A temperature sensor 53 is arranged in the attachment channel 39 or inthe cover element 28 and a temperature sensor 54 is arranged in theprofile body 12 or in the flow channel section 15. Both temperaturesensors 53 and 54 are connected to a PLC (not shown here) for regulatingthe temperature.

For disassembly to clean the heat exchanger 10 it is solely necessary toremove the screws 34 from the cover element 28 and thus to disconnectthe cover element 28 from the profile bodies 11 and 12, the sleeveelements 17 then being able to be pulled out of the flow channelsections 13 to 16. The flow channel inner surface 19 can now bemechanically cleaned easily, if necessary, the base element 29 alsobeing able to be removed from the profile bodies 11 and 12 easily byloosening the screws 34. The sleeve element surface 20 which is thenexposed can also be cleaned easily.

1. A heat exchanger for heating flowable media, in particularhigh-viscosity materials, coating materials, or the like, said heatexchanger comprising: a profile body having at least one flow channelsection of a flow channel of the heat exchanger; a heating devicearranged in the profile body, the heating device having at least twoelectrical heating elements; a first heating element of the heatingdevice is arranged in a heating element receptacle implemented in theprofile body; and a second heating element of the heating device isarranged in a sleeve element of the heating device, the sleeve elementbeing arranged in the flow channel section implemented in the profilebody in such a manner that the heating elements are sealed in relationto the flow channel.
 2. The heat exchanger according to claim 1, inwhich the heat exchanger includes a plurality of profile bodies arrangedin parallel.
 3. The heat exchanger according to claim 1, in which theheat exchanger includes a cover element and a base element, which areeach arranged on profile ends of the profile body.
 4. The heat exchangeraccording to claim 3, in which attachment channels of the flow channelare implemented in at least one of the cover element and/or in the baseelement.
 5. The heat exchanger according to claim 3, in which at leastone connection channel for the connection of flow channel sections isimplemented in at least one of the cover element and in the baseelement.
 6. The heat exchanger according to claim 3, in which the sleeveelement is fixedly connected to the cover element.
 7. The heat exchangeraccording to claim 1, in which the flow channel sections and the heatingelement receptacle are implemented as passage boreholes in the profilebody in the longitudinal direction of the profile body.
 8. The heatexchanger according to claim 7, in which the sleeve element has apolygonal cross-section.
 9. The heat exchanger according to claim 8, inwhich the sleeve element has a peripheral surface, and a plurality oflongitudinal grooves are distributed on a periphery of the peripheralsurface in such a manner that the sleeve element has a star-shaped crosssection.
 10. The heat exchanger according to claim 8, in which anexternal diameter of the sleeve element essentially corresponds to aninternal diameter of the flow channel sections.
 11. The heat exchangeraccording to claim 10, in which a plurality of partial channels of theflow channel sections are implemented between the sleeve element and theprofile body.
 12. The heat exchanger according to claim 1, in which theheat exchanger has heating elements in a ratio of two second heatingelements to one first heating element.
 13. The heat exchanger accordingto claim 1, in which the heat exchanger has an attachment device forattaching the heating elements on the cover element.
 14. The heatexchanger according to claim 1, in which at least one temperature sensoris arranged in the flow channel.
 15. The heat exchanger according toclaim 1, in which the flow channel is implemented as meandering.
 16. Theheat exchanger according to claim 1, in which the heat exchanger has aninsulation device.